The gaseous anesthetics halothane and enflurane were found to reduce the incorporation of 13C from infused 13C-glucose into both glutamate and GABA in all areas examined. However the turnover rate of GABA and the concentrations of glutamate and GABA were unaffected. Pentobarbital, in anesthetic doses, also reduced the incorporation of 13C into both glutamate and GABA, but in this case the turnover rate of GABA was significantly reduced in accumbens, caudate, substantia nigra and septum. The anticonvulsants, diphenylhydantoin and diazepam, have different profiles of activity on GABA turnover rates. Diphenylhydantoin is selective for the accumbens and diazepam reduces the GABA turnover rate in accumbens, caudate and septum.